An amorphous metal strip has a characteristic of low loss compared to a silicon steel plate, and is used for a transmission and distribution transformers or an iron core of a dynamo-electric machine as a material of a soft magnetic. The amorphous metal strip may be obtained by rapidly cooling a metal melted body on a cooling role that is rotated at a high rate, and has a principle limit in which the thickness of the plate is in the range of 10 to 50 μm. In addition, since the amorphous metal strip is largely distorted during the rapid cooling, if the annealing heat treatment is not performed at 300 to 600° C. the soft magnetic characteristic cannot be sufficiently obtained. In addition, the amorphous metal strip is embrittled by the heat treatment. In order to obtain the required strength for a structure, before the amorphous metal strip was subjected to heat treatment, the amorphous metal strip was processed to have a desirable shape, and was impregnated and hardened an epoxy resin and the like after the heat treatment.
To overcome this problem, Japanese Unexamined Patent Application Publication No. Sho58 (1983)-175654 discloses that a polyimide resin or a polyamideimide resin having excellent heat resistance is applied on an amorphous metal strip, dried, pressed, and subjected to annealing heat treatment. In detail, the resin having heat resistance is applied on both sides of the amorphous metal strip for laminating, a solvent is dried at a temperature of 200° C. or more for 1 min, the amorphous metal strips are pressed and attached to each other by using a pressing roll, the strips are heated in the oven under nitrogen atmosphere, and finally the laminated strips are wound and recovered.
In addition, Japanese Unexamined Patent Application Publication No. 2002-164224 discloses that the resin having heat resistance is applied on the surface of the amorphous metal strip, and thermally pressed by a heat press to form a laminate. In other words, the amorphous metal strip laminate having the weatherproofing characteristics may be obtained by laminating the amorphous metal strips on which the resin having high heat resistance is applied and heating and attaching the amorphous metal strips.
In addition, Japanese Unexamined Patent Application Publication No. 2004-90390 or Japanese Unexamined Patent Application Publication No. 2004-95823 discloses that a polyamide acid solution is applied on an amorphous metal strip, preliminarily dried at 130° C., the degree of imidization of the polyamide acid solution is increased at a temperature of 250° C. or more, amorphous metal strips are laminated, and the strips are pressed at a temperature of 250° C. or more while pressure is applied in a laminating direction. It discloses that the amorphous metal strip laminate produced by using the above process may be used as desirable products without an inflated surface.